In recent years, a number of new service features have been provided by an enhanced telephone network, sometimes referred to as an Advanced Intelligent Network (AIN). In an AIN type system, local and/or toll offices of the public telephone network detect one of a number of call processing events identified as AIN "triggers". For ordinary telephone service calls, there would be no event to trigger AIN processing; and the local and toll office switches would function normally and process such calls without referring to the central database for instructions. An office which detects a trigger will suspend call processing, compile a call data message and forward that message via a common channel interoffice signalling (CCIS) link to an Integrated Service Control Point (ISCP) which includes a Multi-Services Application Platform (MSAP) database. If needed, the ISCP can instruct the central office to obtain and forward additional information. Once sufficient information about the call has reached the ISCP, the ISCP accesses its stored data tables in the MSAP database to translate the received message data into a call control message and returns the call control message to the office of the network via CCIS link. The network offices then use the call control message to complete the particular call.
An AIN type network for providing an Area Wide Centrex service was disclosed and described in detail in commonly assigned U.S. Pat. No. 5,247,571 to Kay et al., the disclosure of which is entirely incorporated herein by reference. In AIN type systems such as disclosed in the Kay et al. Patent, announcement and digit functions may be required for certain specific services. For example, a caller may be prompted by a tone or speech announcement to enter a personal identification number (PIN) before obtaining a selected service or modifying certain stored parameters relating to the subscriber's AIN service. In prior art AIN systems, a switching office of the public telephone network would generate the announcements from some internal platform.
Switched based announcements have a number of serious drawbacks. First the capacity of the internal announcement platforms has been limited, thereby limiting the number and variety of announcements which an AIN service can utilize. As AIN services become more sophisticated, a need arises to provide more announcements than such platforms offer, for example to allow subscribers to customize the announcements for their own personalized services. Adding extra announcement capacity to a number of different telephone switching offices is expensive. Often the needed extra announcement equipment can be obtained only from the original switch vendor, in view of the need for compatibility of such equipment with the switch itself.
Also, any service specific announcements must be loaded onto each switch providing the particular AIN service. Loading new announcements on large numbers of switching systems is time consuming and may require the services of expert personnel provided only by the switch equipment vendor.
Accordingly, a need exists for some platform to provide readily adaptable means to add and change announcements to an AIN, without direct addition of equipment in each central office switching system. The platform should also serve to centralize announcement capabilities to some extent, so that announcement reprogramming does not always require reprogramming some equipment for every single switch through which an enhanced service is offered.
A need also exists to provide a convenient platform to add further equipment to facilitate still further enhanced features, such as services based on speech recognition, mail services, etc., without requiring addition to or modification of equipment within the central office switching systems for each such further enhanced service feature.
Proposals have been made to add nodes to the telephone network, separate from the switching offices, to provide announcements and related enhanced service features. For example, U.S. Pat. No. 4,827,500 to Binkerd et al. discloses an announcement point which provides messages to callers, receives dialed digits and/or speech signals for input information from callers and exchanges appropriate data with a remote central 800 number database. The communication between the announcement point and the 800 database apparently goes through the same interoffice signalling network used in routing of calls between switching offices. Any new or additional messages exchanged between the 800 database and the announcement platform will inherently increase the traffic load on the interoffice signaling network. A substantially similar network is disclosed in Weisser et al., "The Intelligent network and Forward-Looking Technology," IEEE Communications Magazine, December 1988, pp. 64-69.
U.S. Pat. No. 5,208,848 to Pula teaches connection of one or more Intelligent Peripherals (IP's) to a single switch. Reprogramming announcements for a new service presumably would require reprogramming each IP connected to each switch in the network. Also, although Pula discloses a common channel signaling link to the switch, there is no specific suggestion of any interaction of the IP with a higher level data base. As in the Binkerd et al. Patent, if any interaction with a higher level database were added, the added communication traffic to that database would have to go through the common channel signaling link and would increase traffic loading on that critical link.
U.S. Pat. No. 5,206,901 to Harlow et al. discloses a service circuit node which plays announcements, collects digits and communicates with an Service Control Point (SCP) database to update intelligent network service files. The service circuit node serves a plurality of switching offices, apparently by routing calls through the public switched telephone network to the one service circuit node. As in the Binkerd et al. and Pula systems, the communications between the service circuit node and the SCP apparently go through the switching office directly connected to the service circuit node and the signaling channel which carries queries and responses between that switching office and the SCP, and creates increased traffic on the signaling network. Attention is also directed to Shah et al., "Application of a New Network Concept for Faster Service Deployment," International Conference on Communications '88, Jun. 12-15, 1988, IEEE Communications Society, Conference Record, Volume 3, pp. 1327-29.
Accordingly, any new node added to the AIN network to offer the enhanced announcement capabilities and other service features, through interactions with the central database, should not increase traffic on the interoffice signaling network and/or the network which carries signaling traffic between the database and the network switching systems, as in the prior art networks.